This means that for the stats other than HP, assuming a neutral nature:

Stat with 0 EVs = 2 × Base Stat + 36 = 2 × (Base Stat + 18)
Stat with 252 EVs = 2 × Base Stat + 99 = 2 × (Base Stat + 49.5)
To calculate the statistical damage, we multiply the attack or special attack stat by the move power. However, since the stat is always twice a number, the statistical damage will always end up as being twice a number as well. Hence, the normalized stats can be defined as being half the actual stats for simplicity purposes (rounding 49.5 up to 50):

Normalized Stat with 0 EVs = Base Stat + 18
Normalized Stat with 252 EVs = Base Stat + 50
For the HP stats, we write them down in this way first:

HP Stat with 0 EVs = 2 × Base HP + 141 = 8 × (Base HP ÷ 4 + 17.625)
HP Stat with 252 EVs = 2 × Base HP + 204 = 8 × (Base HP ÷ 4 + 25.5)
Since the statistical defense is equal to the HP and Defense stats multiplied by each other, we again can use one eighth of the HP stat multiplied by half the Defense stat instead, and the statistical defense will always be one sixteenth of what it should be. Hence, we can define the normalized HP stat as being one eighth of the real HP stat, rounding the numbers from 17.625 to 18 and from 25.5 to 25. This is simple since we still end up adding 18 for the 0 EV normalized HP. Thus: